S. Mahunka szerk.: Folia Entomologica Hungarica 58. (Budapest, 1997)

ROVARTANI KÖZLEMÉNYEK LVIII 1997 pp. 221-225 The history of the Symphyta fauna of the Carpathian Basin (Hymenoptera). Part I L. Zombori and V. Ermolenko The history of the Symphyta fauna of the Carpathian Basin (Hymenoptera). Part I - Authors give a brief outline of the climatic changes having taken place in the Upper Pleistocene that had a drastic effect on the composition of the plant cover. They review characteristic sawfly species in groups according to ecological requirements or other aspects of interest. They conclude that the formation of the Symphyta fauna of the Carpathian Basin was significantly influenced by European, fiuro-Siberian and pan-Palaearctic faunal elements. On the other hand, the faunal elements of the Holarctic region played a minor role. The great majority of sawflies are primary consumers, consequently, they are strictly attached to their host-plants. Any change in the composition of the plant cover, hence any modification in the biotope heavily influences the formation of their populations, the direction of their adaptation. On the other hand, the establishment of a plant cover, its expansion or regression in space is greatly depending from prevailing weather conditions. In the last interglacial (Riss-Würm) period the weather was much warmer than what is today. Then, basically, the following significant changes occurred: -the thermophilous Mediterranean vegetation expanded northward as far as the Alps-Carpathian line, this far, since these mountain ranges formed a natural barrier, - the deciduous forests spread eastward to West Siberia. Since the third phase (Pomeranian) of the last glacial period some 25 000 years have passed causing severe changes in the composition of the plant cover. The climatic changes, peculiarly enough, may not be characterized by a straight but rather an undulating line. This means that about 22 000 years ago, e.g., in North-West Europe the climate was rather arctic-like, then in the Allerod, some 6-8000 years later, a gradual warming up took place, which, for a short period of time, was followed by a sharp decline in temperature bringing back arctic conditions again. 10-12 000 years ago a dry and cool period set in, followed by a dry and warm spell, then closed by a humid and cool period, some 4000 year ago. In examining the changes that have taken place in the Palaearctic region it is readily conceivable that the western part has undergone greater transformation than the eastern one. Thus, e.g., at the peak of the glacial period, north from the line marked by the Pyrenees-Alps-Carpathians-Black Sea-Caspian Sea, scarcely any wooded territory occurred, instead a cold loessy steppe area was formed occupying vast territories. South of this line, down to the latitude of about 42 degrees, the dominant trees were the pines, while further south the mixed stands were common, and the broad-leaved deciduous forests could develop only at the line of North Africa-Anatolia-Syria.